educational vs superliminary

educational

adj
  • Of, or relating to education. 

  • Instructive, or helping to educate. 

noun
  • A free (or low cost) trip for travel consultants, provided by a travel operator or airline as a means of promoting their service. A fam trip 

superliminary

adj
  • Preliminary, introductory. 

How often have the words educational and superliminary occurred in a corpus of books? (source: Google Ngram Viewer )